1. Field of the Invention
This invention relates to an air cleaning system and more particularly to an odor removal system using wicking fibers incorporating large carbon particles, a dry fine solid carbon powder and chemisorptive reagents.
2. Description of Prior Art
Conventional carbon adsorbents have a broad range of effectiveness against odors. However, such activated carbon adsorptive techniques of removing odor from an air stream are effective only for a relatively short time period, are relatively inefficient at low odor concentration levels, and frequently result in a relatively high pressure differential across the activated carbon filter element. As a result relatively large quantities of activated carbon are required in such filter devices, however, even with the larger amount of activated carbon the relatively large pressure differential problem will still remain. These prior devices are usually operated mechanical on a cyclic bases. An example of an adsorptive technique for the removal of odors is the use of activated charcoal as an odor removing element in a device to purify an air stream. U.S. Pat. No. 4,130,487 shows a filter for liquid or gases which includes activated carbon for removing odors during air filtration. The activated carbon is in an additional layer which is added to the filter material.
In the prior art fibers have had surface coatings ranging from finely divided powder particles to coarse granular particles. The particles have been applied by either an adhesive coating which mechanically retains the particles on the fiber or the powder particles have been embedded on the fiber surface during the tacky stage in the polymer processing. The carbon fiber can also be formed by heating polymer fibers and attaching carbon particles when the polymer is sticky or by using an adhesive to hold the carbon particles to a fiber. The ability to coat various powdered particulate material on a surface of a fiber has generally required an adhesive layer to be used to immobilize and hold the powder particles on the fiber surface. The very act of using an adhesive layer to hold the particles results in a portion of the surface of the powder particles being contaminated by the adhesive and therefore becoming ineffective for applications such as filtration. A balance has to be met between the strength of the immobilization versus the maintaining of effectiveness of the powder layer.
In order to minimize this contamination typically larger particles are often used so that the point of contact between the surface adhesive and powder particles is small. In typical gaseous applications using activated carbon the particles used are most frequently 100 microns and larger; and, finely powdered activated carbon is basically only used in liquid decolorization applications despite the fact that fine powder activated carbon holds the potential of much more rapid kinetics.
It is desirable to provide a compact, economical air filter for the continuous removal of odors which avoids the problems of reduced flow rates, a relatively high pressure differential across the activated carbon filter, and reduced removal efficiency over time.